Transcript Government Affairs Committee Legislative Update

Determining Modifications Required for Adding
CNG or LNG Vehicles to Existing Maintenance Facilities
Stephe Yborra
Director of Market Analysis, Education & Communications - Clean Vehicle Education Foundation
Director of Market Development - NGVAmerica
Today’s Agenda
•
•
•
•
Define the Problem/Opportunity
Review Applicable Codes & Standards
Intent /Rationale/Assumptions Behind Codes’ Development
Assess Current Activities in Facility, Potential Practices and
Approaches to Reduce Modification Requirements
• Discuss Applicable Code Requirements for CNG and LNG in
“Major Repair” Facilities
• Maintenance Facility “Best Practices” When Incorporating
CNG/LNG Vehicle into Your Fleet
Defining the Problem/Opportunity
• NGV deployment is accelerating quickly, especially in fleet sector.
– Economies of scale favor RTB and P2P fleets’
adoption; most have centralized service facilities
– Regional/long haul trucking and fueling
operations will necessitate more ubiquitous
CNG-/LNG-capable service garages
• Lack of familiarity with NGV technology and applicable codes
among fleets, design consultants and AHJs
– Codes are “performance” docs, relying on hazard assessment, mitigation
– Diversity of facility designs/construction leads to variable interpretations
– Conflicting codes, outdated government guidance and vendor misinformation
exacerbate confusion and over-cautiousness, leading to overly expensive retrofits
• Opportunity: Knowledge/light on subject can avoid costly errors
and facilitate wider adoption of NGVs more quickly
Properties of CNG and LNG
•
•
•
•
•
•
Natural gas: 88-99% methane (nat’l avg: 93%)
Methane is CH4 (low carbon, energy-dense fuel)
Lighter than air (specific gravity: .55-.65)
Limited combustion ratio (5-15%)
High ignition temperature: 1000+F
Colorless, odorless, non-toxic substance
Ethane
Propane
Butane
Pentane
Hexane
Other
Methane Molecule
• Compressed Natural Gas (CNG)
– Onboard fuel storage: 3600psi
– Mercaptan is added to L/CNG
• Liquefied Natural Gas (LNG)
–
–
–
–
Cryogenic liquid @ -260F;
Methane content: ~95+%
1 cu ft of LNG = 600 cu ft of natural gas @ atmospheric pressure; 3.5 lbs/gallon
Liquid LNG is not ignitable; vaporizes @ approx ~ -155F (lighter than air).
Applicable Codes to Vehicle
Maintenance Facilities
•
•
•
•
International Code Council’s Intl Fire Code (IFC 2012)
International Mechanical Code (IMC 2012)
International Building Code (IBC 2012)
National Fire Protection Assoc. (NFPA) 30A (2012) Code for Motor
Fuel Dispensing Facilities and Repair Garages
• NFPA 52 (2010) Vehicular Gaseous Fuel Systems Code
• NFPA 88 (2007) Standards for Parking Structures
• These national codes are voluntarily adopted by states and local
jurisdictions. Local codes often are not the most recent versions of national
model codes (adoption often lags behind). Local AHJ is final decisionmaking authority and may enforce additional requirements.
Code Intent/Rationale/Assumptions
• Most CNG-/LNG-related codes developed in mid-late1990s based on
perceived hazards based on experience of code committees
– Primary CNG concern: Unintended release in enclosed space.
• Early PRD’s designs were flawed and/or they were improperly selected and the
result was unintended venting of CNG cylinders (most were transit applications).
• Codes developed based on 150% of largest CNG cylinder (50% safety factor).
• US FTA issued facility “guidance” tied to funding (1996-97) that went far beyond
current codes. PRD standards were revised but FTA guidance still in place
• Not a single premature PRD failure/release in 10+ years.
Code Intent/Rationale/Assumptions
• Most CNG-/LNG-related codes developed in mid-late1990s based on
perceived hazards based on experience of code committees
– Primary CNG concern: Unintended release in enclosed space.
– Primary LNG concerns: Venting due to pressure build-up, and liquid release
due to puncture
• Vacuum insulated LNG tanks will still absorb energy and thus a 15psig/day energy
gain leads to hold time of 6-7 days before venting. There are various operational
procedures to minimize potential for release during planned maintenance activity.
• No record of a LNG liquid spill in a maintenance facility
• Empirical/CFD research underway to better model NG behavior
Evaluate Shop Activities, Segregate, Modify
• IFC and NFPA 30A exempt minor repair facilities from code
requirements specific to CNG and LNG.
– IFC 2211.7 exempts garages that do not work on fuel systems or do not
use open flames or welding from all additional requirements
– NFPA 30A exempts garages that do not perform:
• Engine overhauls, painting, body & fender work, any
repairs requiring draining of vehicle fuel tanks
– NFPA 30A define minor repair facility maintenance activity as:
• Lubrication, inspection, engine tune-ups, replacement
of parts, fluid changes, brake system repairs, tire rotations
and similar routine maintenance work
Evaluate Shop Activities, Segregate, Modify
• IFC and NFPA 30A exempt minor repair facilities from code
requirements specific to CNG and LNG.
• To avoid costly modifications, consider:
– Segregating major repair and minor maintenance activities into separate
physical areas; adding NGV-specific bay(s) for major repairs
– Defueling CNG and/or LNG vehicles before entering major repair area
Diesel and gasoline vehicle repair / maintenance
CNG/LNG minor maintenance and (defueled NGV) major repair
CNG/LNG major repair
Existing Code Requirements by Category
(as it relates to maintenance/repair and parking* facilities)
Modification Category
Code Reference
Ventilation Category
IMC (2012) Table 403.3;
NFPA 88A (2007) 5.3.2
IFC (2009) 2211.7.1, 2211.1.1, 2211.7.1.2;
NFPA 30A (2012) 7.5.1, 7.5.2, 7.5.3, 7.5.4, 7.4.7.2, 7.4.7.3
Ventilation in Pits
IFC (2009) 2211.3;
NFPA 30A 7.4.5.4
Gas Detection
IFC (2009) 2211.7.2, 2211.7.2.1, 2211.7.2.2, 2211.7.2.3;
NFPA 30A (2012) 7.4.7, 7.4.7.1, 7.4.7.2, 7.4.7.3, 7.4.7.4
Sources of Ignition
NFPA 30A (2012) 7.6.6
Electrical Classification
NFPA 30A (2012) 8.2.1
Preparation of vehicles
For Maintenance
IFC (2009) 2211.5
Maintenance and
Decommissioning of containers
NFPA 52 (2010) 6.13, 6.14
No
Ventilation
Rate = 1 cu
ft/sq ft
Facility Modifications to
Accommodate Work on
CNG/LNG Vehicles
Bring ventilation
rates up to code
Yes
Garage Type
No modifications
required by the
codes
Minor Repairs Only
Major Repair Garage
Approval by AHJ
required
Natural
Type of
ventilation
LNG or both fuels
Mechanical
Fuel Type to
add to garage
CNG only
LNG or CNG
Inspect and prepare NGV
prior to performing
maintenance
Ventilation rate
should be 5 ACH
Install gas detection
system as required by
codes
Install Fuel
Appropriate Defueling
System
No gas detection
system required
Space is a Class 1
Division 2 Classified
location
Less than 4 ACH
Ventilation rate
within 18” of
ceiling
4 ACH or more
Space is not considered a
classified location
Approval by AHJ
required
Mechanical
Ventilation rate
should be 5 ACH
Electrical
Classification
Natural
Type of
ventilation
Sources of
ignition
Open flames and
+750°F Surfaces
Remove the sources of
ignition in areas subject
to ignitable mixtures
Facility Modifications to
Accommodate Work on
CNG/LNG Vehicles
Ventilation
Rate = 1 cu
ft/sq ft
1. Does existing maintenance facility meet
ventilation code?
A.
B.
IMC 403.3 requires repair garages (of all
vehicle fuel types) to have minimum
ventilation rate of .75 cfm/sqft
NFPA 88A 5.3.2 requires 1.0 cfm/sqft for all
parking structures. Would seem to
indicate that all service garages be
considered parking structures
Result: 1cfm/sqft
No
Bring ventilation
rates up to code
Facility Modifications to
Accommodate Work on
CNG/LNG Vehicles
1. Operation of Ventilation in
Major Repair Facility
with CNG Vehicles
A.
B.
C.
D.
No
Ventilation
Rate = 1 cu
ft/sq ft
Bring ventilation
rates up to code
Yes
Garage Type
No modifications
required by the
codes
Minor Repairs Only
Major Repair Garage
Fuel Type to
add to garage
CNG only
IFC 2211.7.1
i.
Continuous operation except when
interlocked with with lighting circuit.
NO METHANE DETECTION REQUIRED
FOR ODORIZED CNG.
ii. Rate = 1cfm/12 cu ft of space (5 ACH)
NFPA 30A
i.
Silent on operation requirements for CNG
repair facilities (only for fuel dispensing
facilities). NO METHANE DETECTION FOR
ODORIZED CNG.
Both allow AHJ to allow natural ventilation
No mention by either code re CNG-specific
ventilation rate for pits (Clue: lighter than air)
Type of
ventilation
Mechanical
Ventilation rate
should be 5 ACH
No gas detection
system required
Natural
Approval by AHJ
required
Facility Modifications to
Accommodate Work on
CNG/LNG Vehicles
Ventilation
Rate = 1 cu
ft/sq ft
No
Bring ventilation
rates up to code
Yes
Garage Type
No modifications
required by the
codes
Minor Repairs Only
Major Repair Garage
1. Sources of Ignition
A.
B.
Fuel Type to
add to garage
IFC 2211.3
i.
Only addresses liquid
fuels re no ignition sources
within 18” of FLOOR (also
referenced in IBC, IMC, NFPA 70)
NFPA 30A 7.6.6
i.
Requires elimination of open flames
and/or surfaces with temps of 750°F
or more (e.g. , direct-fired unit
heaters, infrared heaters).
ii. Typically means use of indirect
heating systems with ductwork, etc
CNG only
Natural
Type of
ventilation
Approval by AHJ
required
Mechanical
Ventilation rate
should be 5 ACH
No gas detection
system required
Sources of
ignition
Open flames and
+750°F Surfaces
Remove the sources of
ignition in areas subject
to ignitable mixtures
Facility Modifications to
Accommodate Work on
CNG/LNG Vehicles
1. Sources of Ignition - Electrical
A.
B.
Ventilation
Rate = 1 cu
ft/sq ft
No
Bring ventilation
Does HVAC system effectively
ventilate at 4 ACH here?
rates up to code
Yes
Garage Type
Major Repair Garage
IFC 2211
CNG only
Fuel Type to
i.
No specific reference
add to garage
to CNG, LNG
NFPA 30A 8.2.1
i.
Areas within 18” of CEILING are Class I,
Division 2 unless that area has at least 4 ACH.
AHJ will have to evaluate if roof type and
construction methodology allows for effective
ventilation to meet 4 ACH
ii. If < 4 ACH, then electrical must meet Class 1,
Division 2 or be moved out of 18” ceiling zone
Space is a Class 1
Division 2 Classified
location
Less than 4 ACH
No modifications
required by the
codes
Minor Repairs Only
Ventilation rate
within 18” of
ceiling
Electrical
Classification
4 ACH or more
Space is not considered a
classified location
Natural
Type of
ventilation
Approval by AHJ
required
Mechanical
Ventilation rate
should be 5 ACH
No gas detection
system required
Sources of
ignition
Open flames and
+750°F Surfaces
Remove the sources of
ignition in areas subject
to ignitable mixtures
Ventilation
Rate = 1 cu
ft/sq ft
Facility Modifications to
Accommodate Work on
CNG/LNG Vehicles
No
Bring ventilation
rates up to code
Yes
Garage Type
Minor Repairs Only
No modifications
required by the
codes
Major Repair Garage
Approval by AHJ
required
Natural
Type of
ventilation
LNG or both fuels
Mechanical
Ventilation rate
should be 5 ACH
A.
Install gas detection
system as required by
codes
B.
C.
Fuel Type to
add to garage
Ventilation in major repair
facility with LNG Vehicles or
both LNG and CNG Vehicles
IFC 2211 IFC 221.7.1
i.
Continuous operation of ventilation system
@ 1cfm/12cu ft (5 ACH) except when
interlocked with gas detection system for
LNG.
NFPA 30A 7.4.7
i.
Must interlock ventilation system and
methane detection system
Both permit AHJ to allow natural ventilation.
Regardless of ventilation strategy, LNG requires
methane detection system
No
Ventilation
Rate = 1 cu
ft/sq ft
Facility Modifications to
Accommodate Work on
CNG/LNG Vehicles
Bring ventilation
rates up to code
Yes
Garage Type
No modifications
required by the
codes
Minor Repairs Only
Major Repair Garage
Approval by AHJ
required
Natural
Type of
ventilation
LNG or both fuels
Fuel Type to
add to garage
1. Sources of Ignition
Mechanical
A.
Ventilation rate
should be 5 ACH
B.
Open flames and hot
surfaces – same as CNG
Electrical Classification –
same as with CNG
Install gas detection
system as required by
codes
Space is a Class 1
Division 2 Classified
location
Less than 4 ACH
Ventilation rate
within 18” of
ceiling
Electrical
Classification
4 ACH or more
Space is not considered a
classified location
Sources of
ignition
Open flames and
+750°F Surfaces
Remove the sources of
ignition in areas subject
to ignitable mixtures
Facility Modifications to
Accommodate Work on
CNG/LNG Vehicles
No
Ventilation
Rate = 1 cu
ft/sq ft
Yes
Garage Type
Minor Repairs Only
Major Repair Garage
1. Regardless of ventilation
system operation, methane
detection requirements,
interlocking, etc….
A.
B.
C.
Inspect/prepare your NGV
i.
IFC 2211.5 – Isolate fuel
container from rest of
system
ii. Inspect for leakage
NFPA 30A – No mention
RP: Operate NGV until it stalls
after isolating fuel source
Bring ventilation
rates up to code
Fuel Type to
add to garage
LNG or CNG
Inspect and prepare NGV
prior to performing
maintenance
No modifications
required by the
codes
Facility Modifications to
Accommodate Work on
CNG/LNG Vehicles
1. Maintenance/decommissioning
of fuel containers
A.
B.
C.
CNG cylinders have specific
end-of-useful life date (see
label). LNG tanks do not.
NFPA 52.6.13 (2013):
Written procedures should be in
place for inspection and
decommissioning of CNG
cylinders. (Training of staff is
recommended)
NFPA 52.6.14 (2013):
Major repair garage should
install appropriate defueling
apparatus (capture or direct
atmospheric venting)
No
Ventilation
Rate = 1 cu
ft/sq ft
Bring ventilation
rates up to code
Yes
Garage Type
Minor Repairs Only
Major Repair Garage
Fuel Type to
add to garage
LNG or CNG
Inspect and prepare NGV
prior to performing
maintenance
Install Fuel
Appropriate Defueling
System
No modifications
required by the
codes
Shop Design/Modification Considerations
Diesel and gasoline vehicle repair / maintenance
CNG/LNG minor maintenance and (defueled NGV) major repair
CNG/LNG major repair
• Interior walls will have a 2-hr fire rating and be continuous from
floor to ceiling
• For major repair area, at least one wall shall be an exterior wall and
primary access shall be from the outside
• Interior access between minor and major repair areas shall be
through self-closing fire door with AHJ approved rating
• The minor and major repair areas shall have separate ventilation
systems
Summary
• Current guidance is vague; many costly “myths” about requirements prevail;
confusion within design, vendor and code enforcement community
• Guidance is based on assessing risks and modifying accordingly
• Modifications only if “major repairs” are to be performed
– If no CNG system work is to be performed, i.e., basic maintenance (e.g. brakes, etc)
– no modifications required
– If CNG work is to be performed, modifications may be needed
– Consider segregating major repair and minor maintenance areas
• Key considerations in whether or not – and to what extent – to modify:
–
–
–
–
–
Ventilation levels; properly designed ventilation should eliminate “ignitable mixture”
Elimination of hot surfaces above 750⁰F (e.g. indirect heat or AHUs)
Modification of electric only if within 18” of ceiling if minimum ACH is not achieved
Methane detectors not needed for CNG; only for non-odorized gas (i.e., LNG)
Not necessary to install “explosion proof” switches, sockets or redo all electrical
systems
• R&D underway to determine ppm levels, dispersion models, etc